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wow! this is really very informative. thanks sir for this post.
but i have a question. what is the valve clearance for a 200cc engine? is all 200cc engine have the same valve clearance? if so i can do my own DIY on my valve clearance for the first time
it depends on valve system -pushrod or chain drive - so refer to service manual if available , if not find the most similar engine that has the proper service manual
at last take the exhaust a little more lose compare to inlet on pushrod like GS engine like honda cg and same values for GY engine like QM200.
Today checked the valve clearences, my bike is one of the Turkish version of QM200GY, 2006 Pioneer Takashi with 6300 kms on the clock.
I measured the inlet was 0.10 mm as well as the exhaust was 0.10 mm too, lucky me... I belive these are the factory settings..
Left them alone and closed the lids...Will check again after 5000 kms..
My personal opinion is; 0.10 mm clearence for both inlet and exhaust valves is the best value for these bikes, because, my bike starts at a second even in cold mornings, no valve noice at normal operation temperatures, very little valve noice only when engine is extremely hot.., Bike pulls like a train, incredible powerfull for a 200cc bike even on high gears at low speeds, don't have to lower the gear, just pull the gas and she speeds up..
Quote:
Originally Posted by volksjagger
Do you have a picture showing such vaccum line needed to be replaced? I'm have the same issue. I decided to break the rubber seal on the gas cap for a temporary fix which isn't good in the long run because it allows water, moisture, dirt, ect to get into the gas tank.
Good evening everyone. last sunday i changed my oil and checked the valve as well. this time i tried the .10mm in and .10mm ex. and it feels really better on my bike.
before i was using .08mm in and .10mm ex. it runs good but the engine comes too hot and it runs no well after a long ride, i mean im not satisfied with the topspeed.
now the new valve clearance will be tested tomorrow if it will be really better from the old clearance after my long ride.
Try 0,15 mm for exaust valve.
whats up guys? wheeew long ride is done. im so happy and contented today with the acceleration and less vibration of the engine and also less noise. but im disappointed with my top speed. i feel like my bike is tired even from the first few kilometers. hmmm dont really know whats the best valve clearance for my bike. the manual says 0.02-0.05 mm only but thats too close for me and the engines comes to hot
With the clearance you mentioned, you will burn valves.
yes sir youre right. thats why since sir chinaV posted this thread and i had read it, i did my DIY valve clearance job. first i used the 0.06mm in and 0.08mm combination and it did gets good, then 0.08mm in and 0.10mm ex and it did gets better and now im searching for the best. my current 0.10mm in and 0.10mm ex is good but not really good. so now sir zorge you think is it good if i try the 0.15mm ex while still my in is 0.10mm?Quote:
Originally Posted by Zorge
Please, do not "sir" me - I feel so uncomfortably. In this forum we are all equal - C-moto army's combatants.
A propos valve clearances: not so long ago, in our local moto forum, once again was discussed about the issue. Again, the practice proved that 0.1 on intake and 0.15 on exhaust is the winning combination.
Something like disclaimer: previously written is related to climate, fuel, oil and Qingqi/Pioneer motorcycles ridden in my part of the world.
im so sorry, i dont mean anything, i was only used to it in our country forum that every ones calling each other sir as a sign of respect. and thank you so much brother zorge, ill do that combination to my next valve clearance. probably next change oil. yahowww... cant wait to see the difference.
Don't be sorry - there is no reason for that. Different countries, different customs.
Nice thread. But loose valves means less lift and that means less power. Most China bikes have valve clearances listed with engine specs. Just surf the engine make for these important clearances.
Unfortunately this is not true. Very few companies post accurate specs on their engines, and almost everyone relies on using the specs from whatever Japanese engine they copied.Quote:
Originally Posted by Real4real
Cheers!
ChinaV
Below are the specs for the engine in my Saga 250cc enduro found on the manufacturer or distributers web site.
ModelZS167FMM (CG250)
ManufacturerChongqing Zongshen
TypeSingle-cylinder, vertical, four-stroke, air-cooled
Maximum power and corresponding speed kW / (r / min)11.5 / 6500
Rated power and corresponding speed kW / (r / min)11.0 / 6500
Maximum torque and corresponding speed N • m / (r / min)17.5 / 5500
Minimum Idling speed r / min1400 ± 100
Cylinder diameter mm67
Piston stroke mm65
Total displacement ml229.2
Compression ratio9.2:1
Ignition timingBefore TDC 15 ° (1400r/min)
InletThe following set camshaft
IgnitionC.D.I electronic ignition
LubricationPressure, splash compound
Valve Timing*valve clearance* mm0.05-0.07
Clutch typeManual wet multi-plate
Constant mesh five-speed two-stage variable speed driveReduction ratio"Primary: 3.333; a file: 2.909,Second gear: 1.867; third gear: 1.389,Fourth gear: 1.150; five files: 0.9545 "
Starting method* Electric start and kick-start
Spark Plug TypeJapanese Model D8EA (NGK) or D8TC (LG)
Gasoline brands≥ RQ90
Oil gradeSF15W / 40
ML total capacity of oil1100
Dimensions mm358 × 324 × 458
Be cautious using specs to maintain your newer bike from a design made 40 years ago. Most engines being made in China have better materials and slightly updated designs. Exaust valves are made of harder and/or slightly different materials reducing thermal growth eliminating the need for excessive clearance between rocker and valve. This is done to provide easier starts, quiet operation and the high rpm's achieved in most engines made in China today. Use the original 40 year old design specs as a guide and only as a last resort. The dealers that provide service for these bikes have sevice manuals specific to these newer engines and can provide this infomation as well. It is worth while investing the time to find any specifications direct from the manufacturer for proper operation and life span of your engine.
I agree with ChinaV that most people do use specs from the original 40 year old design when turning wreches on thier bikes, but they do this in error and most cause damage to thier newer engines when using these outdated specs and write it off as poor quality engine from China.
I emailed the manufacturer of ChinaV's 250cc bike or the model that was easily found on the internet, a QM250-2D. ChinaV provided me with a request for info for this bike via private msgs. In less than 24hrs I recived this reponce.
Dear Sir:The clearance is 0.05-0.07mm
Best rgds Director of Sales Department ofJinan Qingqi Foreign Trading Co.,Ltd
Office address:No.369 Chonghua Road, Jinan high&new technology industry zone,China
It is clearly true that 10mins of time on the internet and email can get you the proper specs for your new China bike direct from the manufacturer rather than using outdated specs from the 1970's used on an engine built by someone else. Unlike ChinaV might have done, spend the time to get the specs from the manufacturer, it's well worth the time to have your bike running at it's best.
FYI, The address I have included in this post is public infomation and can easily be found on thier website.
Intake 0.03-0.08mm
Exhaust 0.08-0.13
I believe that is what is the specs on the actual Suzuki version of the engine.
I would not use the numbers you got,. There could be a range for both and they could be different.
How are you interpreting those, why so tight on the exhaust side? Did they offer any explanation as to why it would be different then the original design? Did they offer any reason for the exhaust to be the same as the intake when on the original design they are not?
You cannot get specs from the 1970’s on that engine it is a newer engine, I do not think it has been in production for more then ten years.
I would check mine and see if they fall into the range that Suzuki offers, if so then it would be unwise to tighten the exhaust side as tight as the Jinan suggested range.
I would not trust them, the shop manual I have has allot of obvious errors in it.
I only expressed caution when using specs from another engine manufacturer for our China bikes.
The reason for exaust valves having the same specs is explained above in one of my earlier posts in this thread. Yes I am aware that the exaust valve gets hotter than the intake valve but most engine manufacturers have solved this problem. Different alloys expand at different rates when heated and when you make the exaust valve and intake valve out of different alloys the same expansion from exaust and intake can be achieved, simmilar to titanium valves and connecting rods used in high performance engines to reduce weight and to maintain tight clearances under all engine conditions.
A Chevy V8, Ford V8 and a Dodge V8 all seem very simmilar and all have been swaping design features for years but it would be unwise to use specifications from Chevy to set up a Ford or Dodge engine, right?
I currently have 3 four stroke engines made in China, I have used the manufacturers specs to set the valves on all of them without any problems. I have even had to remove the head from one after years of abuse and found no burnt valves or carbon build up between the valve and seat.
You and others not willing to use the engine manufacturers specs can set your valves however you want but I will continue to set mine according to the manufacturer to ensure my bike run for years.
It was pointed out earlier in this thread that you might get more power from loose rocker to valve clearances but a dragster has more power than most production vehicles but most drag engines only get a few pulls and then need to be rebuilt. This is not something I want for my street legal bike.
I know that China has lacked from making quality products in the past and I do slightly understand people not trusting or understanding the specifications they request you use. It's now 2013 time to move on and except that China does and will continue to produce a good engine and has the skills in place to make a good product. The only problem engines made in China now face is people that feel they are smarter than the engine manufacturers and poorly maintaining thier engines. I have known many so called mechanics with licences do simmilar things you have done and it usualy resulted in a wrecked engine or at least bent valves from what we are talking about and striped bolts from torque specs found from another manufacturer.
You should read your manual with caution as well, most are created in the language of the manufacturer and translated to multiple languages by people that might not have enough mechanical experience to express what is trying to be said, this includes converting measurments. I have delt with this on many CNC machines I have programed, run, maintained and repaired from around the world and any time I had an issue with the manual seeming incorrect it was easily clarified when I contacted the manufacturer.
I agree that you should follow the manufactures specifications, if they are in a professional format that has been verified, that is not the same as getting an email from sales, the only thing sales people are experts at is Bull Shit, for real are you in sales.
The sales department sent the english version of the specs reqested, the request was sent to the enginering department who wrote these specs to sales in Chinese. I have this all in my inbox but didn't feel the need to share this and edit the email addresses to post the requested information here.
I'll give you and E for effort to prove your point.
By the way, the clearences given are the clearences requiered for oil to lubricate the cams, rockers and valves. By setting your exaust clearences loose you are in fact changing the duration of the exaust valve, causing it to close sooner and in some cases increasing the power of the engine. This is incorrect and very poor mechanical practice to gain a half a horse. Some engines allow you to dial in the cams to achieve changing the duration without causing damage to the valve train. Also your rocker to valve clearences increase in modern Chinese engines when the engine gets hot due to the geometry of rocker pivot to valve contact hight together with the thermal growth of the rocker itself.
Please stop posting poor information, there are people visiting this forum for information to maintain thier engines and the info your posting and trying to prove could cause damage to an engine. The clearences your posting to use are old school enginering.
My 2009 China bike uses a Suzuki based engine still in production except for the rocker system, this has been updated with better materials and re-enginered to reduce excessive clearences reducing noise and increasing the max RPM and power output. The Suzuki engine has been in production for a while and the Japanese haven't bothered to update this design because the engine is selling as an entry level power sorce and re-tooling for a couple of horse power isn't economical. Yes I am saying the Chinese engine in my bike is better in some ways than the Suzuki engine it's some what based on.
I have never done sales myself, in fact I am a profesional maker. I have done it all, CAD design of parts and assemblies, pattern making for casting production, machining the parts for assembly and assembly the mechanical finalization of the making process. I have done this for small engine, automotive and large engines with pistons that required a crain to be lifted and many other applications. That's how I know my stuff. Nice try again.
You are obviously an amature mechanic who thinks too much of yourself MJH. I have been clear and reasonable with my experience and defined my reasons for giving the advice I've given. The only thing I have seen from you MJH is insults to the manufacturers of the bikes I thought we all enjoy. Try to dig up some facts or proof of the accusations and poor mechanical practices you so easily pass around.
I want to adjust valves on my YBR250 cos seems that a maintenance check after my China trip (16000km) skipped this part. I told the mechanics to do that and went off to a shop, returned 15min later and they said its been done. I didnt notice any difference in noise and the engine isnt as nippy as for the first few thousands km. After reading this guide i sure it would take them longer than 15min so they just lied to me.....ehhhh
Ill try to do it myself but im not sure about the numbers, found this online
Intake valve: 0.05 - 0.10mm (0.002 - 0.004inch)
exhaust valve: 0.08 - 0.13mm (0.003 - 0.005inch)
can anyone confirm this?
The manufacturer will give you the exact specs to suit your specific engine. Try sending them an email, any that I have tried both China bike and mainstream Japanize manufacturers and they got back to me in a couple of days.
Be sure to try to slip your feeler guage between valve and rocker before you start changing anything, if you can't get the thinest feeler guage in between ajuster and valve this tight valve may be open slightly while your bike is running. If a tight valve*is suspected be sure to check your new settings once cooled down after a good ride. This was the case with my bike at my first 500km check and after I corrected the tight valve this valve must have re-seated and/or knocked out some carbon and tighted up again and required another ajustment.
Good luck and be sure to take your time ajusting your valves. This is one of the most important easy to do settings to get the best performace on any bike.
I would not use that if you found it on Wiki answer.Quote:
Originally Posted by modron
http://wiki.answers.com/Q/Yamaha_Ybr...alve_clearance
They recommend the dealers mechanic do it.
http://ybrclub.com/_files/books/yama...ner_manual.pdf
I would go back to the mechanic and say
你做了什么，是不正确的失去动力
Real4realthanks, I emailed Yamaha customer service, hope they will give me an answer soon. MJH youre correct, its from wiki answers thats why I wanted to confirm this.
Im pretty sure that the mechanics didnt do anything apart from taking the panels off. They were taking it off when I left and putting it on when I came back. Im bit scared of adjusting the valves by myself but one has to learn somehow ;)
Whilst you are waiting.
I am fairly certain that most manufactures will direct you to an authorized service center. They will not likely offer you the specifications that would lead you to do what they recommend having a mechanic do. page 6-12 in the the owners manual.
Its for a 2007 though, but likely is the same as yours.
I would like to add that professional mechanics use authorized publications from the manufactures and all respectable manufactures offer shop manuals….
I have three motorcycles and have three shop manuals, two are Hondas and one is a Qlink, to the best of my knowledge the shop manual for the XP200 is the only existing shop manual for any Chinese manufactured motorcycle, that is not a Japanese motorcycle, that happen to be made in China, like your YBR250.
I do pay mechanics to do work for me, but would never ask them to make an adjustment without making sure they had the specifications. I know the valve lashing clearances on all my motorcycles, I would not buy one that does not offer that in a professional publication that I can readily buy. Which would be just about every Chinese manufactured motorcycle….except the one I own.
The 250cc version of my motorcycle does not offer a shop manual and has no authorized service centers.
The people selling them may say they do…but without a professional shop manual published then how can they authorize a services center? Oh I know they just authorize anyone that buys their stock and sells them.
I am totally sure that the Chinese do not publish service manuals because they cost money and they will get copied, they probably are waiting for others to make them so they can save money and just copy theirs. It is what they do….copy everything, its cheaper.
Thanks MJH,
I didnt even know that something like service manual exists. I did some googling and found one for free but its in spanish. I do speak some spanich but its only conversational, my vocabulary ends with "valvulas". There are a lot of numbers in the chapter about valvulas but I think the ones that I might be looking for are on one of these screen shots below.... any spanish speaker?
I think its the second one cos the first one is rather small hahah ;)
Attachment 13304Attachment 13305
yeah the second is for the valve seats.
the clearances are the same for exhaust and intake on that bike.
there is a note at the bottom about the contacted surface area and that the color blue is removed?